apparmor: add base infastructure for socket mediation

version 2 - Force an abi break. Network mediation will only be
            available in v8 abi complaint policy.

Provide a basic mediation of sockets. This is not a full net mediation
but just whether a spcific family of socket can be used by an
application, along with setting up some basic infrastructure for
network mediation to follow.

the user space rule hav the basic form of
  NETWORK RULE = [ QUALIFIERS ] 'network' [ DOMAIN ]
                 [ TYPE | PROTOCOL ]

  DOMAIN = ( 'inet' | 'ax25' | 'ipx' | 'appletalk' | 'netrom' |
             'bridge' | 'atmpvc' | 'x25' | 'inet6' | 'rose' |
	     'netbeui' | 'security' | 'key' | 'packet' | 'ash' |
	     'econet' | 'atmsvc' | 'sna' | 'irda' | 'pppox' |
	     'wanpipe' | 'bluetooth' | 'netlink' | 'unix' | 'rds' |
	     'llc' | 'can' | 'tipc' | 'iucv' | 'rxrpc' | 'isdn' |
	     'phonet' | 'ieee802154' | 'caif' | 'alg' | 'nfc' |
	     'vsock' | 'mpls' | 'ib' | 'kcm' ) ','

  TYPE = ( 'stream' | 'dgram' | 'seqpacket' |  'rdm' | 'raw' |
           'packet' )

  PROTOCOL = ( 'tcp' | 'udp' | 'icmp' )

eg.
  network,
  network inet,

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>

security/apparmor/include/policy.h

@@ -30,6 +30,7 @@
 #include "file.h"
 #include "lib.h"
 #include "label.h"
+#include "net.h"
 #include "perms.h"
 #include "resource.h"
 
@@ -224,6 +225,16 @@ static inline unsigned int PROFILE_MEDIATES_SAFE(struct aa_profile *profile,
 	return 0;
 }
 
+static inline unsigned int PROFILE_MEDIATES_AF(struct aa_profile *profile,
+					       u16 AF) {
+	unsigned int state = PROFILE_MEDIATES(profile, AA_CLASS_NET);
+	__be16 be_af = cpu_to_be16(AF);
+
+	if (!state)
+		return 0;
+	return aa_dfa_match_len(profile->policy.dfa, state, (char *) &be_af, 2);
+}
+
 /**
  * aa_get_profile - increment refcount on profile @p
  * @p: profile  (MAYBE NULL)